The present invention relates to a torque detector, particularly to a torque detector for detecting a torque applied to a torque transmission shaft which is connected to a load such as a wheel of an automobile.
The conventional torque detector of this type is provided with a detector shaft of which one end is connected to a driving shaft of an engine and the other end is connected to the torque transmission shaft. In this torque detector, the torque applied to the torque transmission shaft is detected by detecting the distortion occurring in the above detector shaft.
The distortion of the above shaft is detected by a detecting means of a strain gauge type comprising a strain gauge of which electric resistance varies in proportion to the distortion, of a magnetic strain type comprising a magnetic strain pipe of which magnetic property varies in accordance with the distortion or of a phase difference type, which detects a phase difference between the distortion occurring at two separated points of the detector shaft.
In the conventional torque detector, applied torque is detected by detecting distortion occurring in the detector shaft so that the detector shaft must be made long in order to improve the accuracy of detection. As a result, the conventional torque detector becomes too large to be mounted on the automobile practically.
It has been required to control the engine and a transmission of the automobile in accordance with the applied torque. Namely, it has been required to control the air-fuel ratio and the ignition timing of engine by detecting the engine torque, to select the most suitable transmission ratio of transmission by detecting the load driving torque which is transmitted to the load side through the transmission, and to select such a transmission timing as to reduce shock to a minimum by detecting both of the engine torque and the load driving torque.